ON-LINE DETECTION OF OLTC MECHANICAL PERFORMANCE

A portable system has been developed for on-line detection of mechanical performance of on-load tap changers in voltage regulation transformers. The measurement is made on the rolling angle of the driving rod connected between the operation mechanism and the switches, the acoustic bursts produced by the contact impacting and the current of the driving electromotor. Based on the measurement, the time sequence of the mechanical events in one switching operation and the force moment of the driving electromotor can be examined, and the decline of on-load tap changer performance can be recognized. The preliminary field tests show that the on-line detection scheme is feasible.